schema: enable getting node data path without list key

There is no way to get a node data path (path without choice/case)
without list keys.

Adds the path_type parameter to the SNode.schema_path() method. This
parameter can takes 3 values:
 - SNode.PATH_LOG: returns the path with schema-only nodes (choice,
   case) included, the default
 - SNode.PATH_DATA: returns the path without schema-only nodes
 - SNode.PATH_DATA_PATTERN: similar to PATH_DATA with list keys added
   (the one used by data_path())

The SNode.PATH_LOG is set by default to not change the original
behavior.
The SNode.data_path() method now calls SNode.schema_path() with
self.PATH_DATA_PATTERN instead of lib.lysc_path().

Here is an example of the output difference between schema_path(),
data_path(), and schema_path(path_type=SNode.PATH_DATA) with a node
included in a choice and a list:
node.schema_path():
/ietf-keystore:keystore/asymmetric-keys/asymmetric-key/private-key-type/private-key/private-key
node.data_path() or node.schema_path(SNode.PATH_DATA_PATTERN):
/ietf-keystore:keystore/asymmetric-keys/asymmetric-key[name='%s']/private-key
node.schema_path(SNode.PATH_DATA):
/ietf-keystore:keystore/asymmetric-keys/asymmetric-key/private-key

Tests have been updated accordingly.

Signed-off-by: Matthieu Ternisien d'Ouville <[email protected]>

libyang/schema.py

@@ -1034,6 +1034,10 @@ class SNode:
         ANYDATA: "anydata",
     }
 
+    PATH_LOG = lib.LYSC_PATH_LOG
+    PATH_DATA = lib.LYSC_PATH_DATA
+    PATH_DATA_PATTERN = lib.LYSC_PATH_DATA_PATTERN
+
     def __init__(self, context: "libyang.Context", cdata):
         self.context = context
         self.cdata = cdata  # C type: "struct lysc_node *"
@@ -1079,22 +1083,19 @@ def status(self) -> str:
     def module(self) -> Module:
         return Module(self.context, self.cdata.module)
 
-    def schema_path(self) -> str:
+    def schema_path(self, path_type: int = PATH_LOG) -> str:
         try:
-            s = lib.lysc_path(self.cdata, lib.LYSC_PATH_LOG, ffi.NULL, 0)
+            s = lib.lysc_path(self.cdata, path_type, ffi.NULL, 0)
             return c2str(s)
         finally:
             lib.free(s)
 
     def data_path(self, key_placeholder: str = "'%s'") -> str:
-        try:
-            s = lib.lysc_path(self.cdata, lib.LYSC_PATH_DATA_PATTERN, ffi.NULL, 0)
-            val = c2str(s)
-            if key_placeholder != "'%s'":
-                val = val.replace("'%s'", key_placeholder)
-            return val
-        finally:
-            lib.free(s)
+        val = self.schema_path(self.PATH_DATA_PATTERN)
+
+        if key_placeholder != "'%s'":
+            val = val.replace("'%s'", key_placeholder)
+        return val
 
     def extensions(self) -> Iterator[ExtensionCompiled]:
         ext = ffi.cast("struct lysc_ext_instance *", self.cdata.exts)

tests/test_schema.py

@@ -282,13 +282,16 @@ def test_iter_tree(self):
 
 # -------------------------------------------------------------------------------------
 class ListTest(unittest.TestCase):
-    SCHEMA_PATH = "/yolo-system:conf/url"
-    DATA_PATH = "/yolo-system:conf/url[host='%s'][proto='%s']"
+    PATH = {
+        "LOG": "/yolo-system:conf/url",
+        "DATA": "/yolo-system:conf/url",
+        "DATA_PATTERN": "/yolo-system:conf/url[host='%s'][proto='%s']",
+    }
 
     def setUp(self):
         self.ctx = Context(YANG_DIR)
         self.ctx.load_module("yolo-system")
-        self.list = next(self.ctx.find_path(self.SCHEMA_PATH))
+        self.list = next(self.ctx.find_path(self.PATH["LOG"]))
 
     def tearDown(self):
         self.list = None
@@ -300,9 +303,11 @@ def test_list_attrs(self):
         self.assertEqual(self.list.nodetype(), SNode.LIST)
         self.assertEqual(self.list.keyword(), "list")
 
-        self.assertEqual(self.list.schema_path(), self.SCHEMA_PATH)
+        self.assertEqual(self.list.schema_path(), self.PATH["LOG"])
 
-        self.assertEqual(self.list.data_path(), self.DATA_PATH)
+        self.assertEqual(self.list.schema_path(SNode.PATH_DATA), self.PATH["DATA"])
+
+        self.assertEqual(self.list.data_path(), self.PATH["DATA_PATTERN"])
         self.assertFalse(self.list.ordered())
 
     def test_list_keys(self):